Improvement in tube-thimbles



ment.

lUNITED, STATES CEAS. COPELAND,

0E NEW YORK, N. Y.

IMPROVEMENT IN TUBE-THIMBLES.

Specification forming part of Letters Patent No. 56,905, dated August7,1866.

To all whom it may concern.'

Be it known that I, CHARLES W. COPE- LAND, of the city, county, andState of New York, haveinvented a new and useful Improvement inTul'ie-Thimbles; and I do hereby declare that the following is a full,clear, and exact description thereof, which will enable those skilled,iu the art to make and use the same, reference being had to theaccompanying drawings, forming part of this specification, in which-Figure lis a perspective view of my improve- Fig. 2 is a plan thereof.Fig. 3 is a side elevation; Fig. 4, a crossfsectional elevation; Fig. 5,a perspective View, showing the` position of my improvement within atube.

Similar letters of reference indicate correspondin g parts.

In the constructionand use of tubular steamboilers,furnaces, and othertubular heating apparatus, it frequently occurs that, 4either fromoriginal proportion or a reduced duty being required, it becomesadvisable, for the sake of economy, to reduce what is technically termedthe calorimeter of the tubes by thimbling the tubes at the dischargingen d, thus reduc` ing the velocity of the current of gases or draftthrough the tubes. This has usually been accomplished by inserting ashort ring or thimble into the outlet end of the tubes. These thimblesare attended with the disadvantages, lirst, `of checking the draft orcurrent equally, or nearly so, on all sides of the tube; secondly, theordinary thimble, by itswprojection within the tube, forms an obstacleto the progress and discharge of the light ashes which, by the ordinaryeftectof the draft, would be carried entirely through the tubes anddischarged from them; but being arrested by the thimble they remainWithin the tube and form a non-conducting coating therein, and thusprevent the economical use of the fuel.

V'lhe ordinary rings or thimbles are also an obstacle in the way ofproperly clearing the tubes of soot and ashes when necessary.

My improvement meets,- and overcomes these objections, and also tends topromote an economy in the consumption of fuel, while my improved thimbleis about one-half as expensive as the ordinary mode of thimbling bycylindrical rings, as already described.

My improvement consists in making the thimble of arch orsemi-cylindrical or crescent form, asshown at A. Its surfaces arebeveled much like the ordinary thimble, as shown in Figs. 3, 4, and 5,and it is driven into and held within the tube like the ordinarythimble.

The position of my improved thimble within the tube B is shown in Fig.5. The thimble A occupies the upper part of the tube, and the thicknessof the thimble is intended to be sufficient to govern the calorimeter ofthe tube to the size required.

-The location of the thimble at the upper part of the tube serves tocheck and detain the hot-ter gases ot' combustion, which naturally riseto the top` of the tube, so as better to allow the absorption of thecaloric by the tubes. l

By the use of my improvement the lower part of the tube is left entirelyopen and unobstructed, so that the light ashes before referred to arecarried through and. discharged from the tubes.

The use of my improvement also permits the free introduction and use ofclearing-instrnments, so that the tubes may be readily and thoroughlycleaned when desired, as the arch-shaped thimbles present no obstructionto the exit of brushings or scrapings when loosened by the instrument.

My improved thiinbles are inserted and removed from the tubes in thesame manner as the ordinary thiinbles.

My improvement is not to be limited or con- `lined to the exact shape ofthe thimble herein substantially as herein shown and described,

so as to govern the calorimeter and reduce the draft without obstructingthe lower part of the tube, as set forth.

CEAS. W. COPELAND.

'Witnesses:

WM. F. MCNAMAEA, ALEX. F. ROBERTS.

